To me your event stresses the importance of "10: Follow-up is not optional"
and after the on-site visit a follow-up e-mail to the client mentioning how all is going well and there are no issues/questions. The e-mail becomes a record should a dispute arise in the future.
Of course there are situations where the follow-up on-site is just not reasonable
as I and my buddies learned over the years...
"There's never time to do it right, but there's always time to do it over"
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